Though I grow both grafted and own-root roses, I’m about ready to dig up the grafted roses and pitch them out because they’re producing so many suckers. What is wrong with my grafted roses?
Ellen Rogers, Richmond, VA
Grafted roses may produce suckers. To minimize suckering that is triggered by stress, give roses optimal growing conditions.
Photo/Illustration: Jennifer Blume
Michael Ruggiero, senior curator of the Peggy Rockefeller Rose Garden at the New York Botanical Garden, replies: The rootstocks of grafted roses can produce suckers, but typically only after experiencing some kind of stress. The types of stress that can trigger sucker growth from a rootstock include diseases such as black spot and powdery mildew, drought conditions, soil drainage so poor the graft union becomes waterlogged, physical damage either to the canes of the rose plant or its root stock or, simply, old age.
If suckers appear, cut them back as close to the rootstock as possible, as they can and will outcompete the desirable grafted plant for nutrients, water, and light. To minimize suckering, provide your rose bushes with optimal growing conditions in full sun and well-drained, neutral soil, making sure that the graft union is buried about an inch deep.
Modern roses such as Hybrid Teas, Grandifloras, and Floribundas, and Old Garden roses like musks, mosses, Portlands, and rugosas are grafted for a number of reasons. The technique of grafting, which unites a scion (a twig, or a young branch) from one rose to the rootstock of another, allows the nursery trade to produce a greater number plants for sale in a shorter period of time. It takes twice as long to produce garden-ready roses from cuttings. Also, since modern roses are less hardy than Old Garden roses, scions from modern roses can easily be grown upon a much hardier rootstock, giving gardeners a chance to grow modern roses in areas where they otherwise could only be grown as annuals.
In general, if your taste in roses leans toward Old Garden types, and you aren’t concerned about the size of the plants that you purchase, you’re better off buying non-grafted roses grown on their own roots. Unfortunately, if you want to grow modern Hybrid Tea roses, they will be grafted plants and you’ll occasionally have to deal with suckers.